1. Field of the Invention
The present invention is directed to the field of web transport mechanisms and more particularly to magnetic tape decks and improvements therein.
2. Description of the Prior Art
Reel-to-reel type tape transport mechanisms, especially those which utilize tape cassettes, are subject to tape fouling. One of the causes of tape fouling occurs when the tape drive mechanism is initially engaged with the tape reels. A rotationally driven capstan engages the tape between itself and a biased pinch roller and pulls the tape across a play/record head. A take-up reel is also rotationally driven, through a slip clutch, to take up the slack in the tape after it passes from the capstan. However, at the instant of initial start-up, a loop often develops between the capstan and the take-up reel before the take-up reel has had a chance to remove all the slack in the tape between the reel and the capstan. Depending upon the slackness of the tape wound on the take-up reel, and the lightness of the tape, the loop sometimes develops sufficient inertia to instantaneously wrap around the capstan, become caught between the incoming tape and the capstan, and be wound thereon. When this capstan windup occurs, the clutch driven take-up reel reverses its direction of rotation, due to the tape being drawn therefrom and wound onto the capstan. The windup continues until it is either audibly detected and stopped by the operator or binds up the capstan/pinch roller mechanism.
When detected and stopped, the tape must be carefully unwound from the capstan by hand. However, in some cases, the woundup tape is folded and wrinkled so badly that it must be discarded.
U.S. Pat. No. 4,348,702; U.S. Pat. No. 4,494,712; and commonly assigned copending U.S. patent application Ser. No. 565,768, now Pat. No. 4,508,280 are incorporated herein by reference, since each discuss this problem and propose separate techniques to overcome it.